You Are What Your Mother Eats

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The old aphorism "you are what you eat" doesn't go far enough, a
new study finds. You may also be whatever your mother eats.

When pregnant monkeys consume a high-fat diet modeled after the
typical American meal plan, their offspring are more anxious and
stressed compared with the offspring of moms that ate more
healthfully during pregnancy, according to the research. While
earlier work uncovered
long-term physical health consequences in offspring of
fat-consuming moms, the new study reveals similar findings about
mental health, said study researcher Kevin Grove of the Oregon
National Primate Research Center in Beaverton, Ore.

Given the similarities between human and non-human primate
physiology and the fact that high-fat diets are the norm in
America, the effect of maternal diet on babies' mental health
"really is scary," Grove told LiveScience.

"Even if we take the offspring, after they're weaned from their
mothers, and put them back onto a normal, healthy diet, their
susceptibility to stress and anxiety still remains," Grove said.
"This really appears to be a permanent issue that occurs in
utero."

Lead study researcher Elinor Sullivan, also of the Oregon
National Primate Research Center, presented the results Monday
(Nov. 15) at the annual meeting of the Society for Neuroscience
in San Diego.

Anxious monkeys

Grove, Sullivan and their colleagues were researching the
metabolic health of Japanese macaque (also known as the snow
monkey) offspring when Sullivan noticed that liver damage and
excess body fat weren't the only legacies carried by babies of
moms on fatty diets. Those offspring also seemed more
high-strung.

The team took a closer look, comparing offspring of moms on a
diet in which 35 percent of calories came from fat with the
offspring of moms that ate healthy diets in which just 13 percent
of calories were from fat. The researchers tracked 23 babies from
moms with high-fat
diets and eight babies from moms with low-fat diets.

After the babies were a month old, the researchers introduced
them to several stressful situations, such as having an unknown
human stand near their cage. In another test, the researchers put
unfamiliar toys like rubber snakes or Mr. Potato Head (so chosen
because the toy's big eyes are "mildly stressful" for an infant,
Grove said) in each baby monkey's enclosure.

The babies of the moms on the fatty diet were overwhelmingly more
freaked out by the toys and stranger, the researchers found. That
was especially true of female monkeys, which were reluctant to
approach the toys (although they responded eagerly to food). The
male offspring of fatty-diet moms were more likely to behave
aggressively, threatening the human intruder in the stranger
test, for example. Overall, the researchers report, 78 percent of
the high-fat diet offspring displayed anxious or aggressive
behavior during the tests, compared with 11 percent of the
healthy-diet offspring.

Healthy diet, healthy baby

Regardless of whether the high-fat-diet moms became obese or
stayed lean, their babies were more anxious, Grove said,
suggesting that it's diet, not obesity, that influences their
offspring's behavior. The problem seems to lie with serotonin, a
neurotransmitter that contributes to feelings of well-being, the
researchers found. The brains of fetuses and babies of high-fat
diet moms showed disruptions in serotonin signaling.

What may be happening, Grove said, is that a high-fat diet
inflammes the placenta, which in turn exposes the developing
fetus to inflammatory proteins called cytokines. Cytokines are
known to disrupt the development of the serotonin system.

The researchers are now investigating ways to reverse the effects
of the high-fat diet. While the damage seems to be done by birth,
altering the maternal diets during pregnancy reduces anxiety
symptoms in offspring, Grove said. That's a lesson human
mothers-to-be should
take to heart, he said.

"Pregnancy is a very vulnerable period in time for the developing
fetus, obviously," Grove said. "But it's also a time of
opportunity for long-term improvement of health in the
offspring."